Sarcopenic phenotype and functional status of skeletal muscles in rheumatoid arthritis patients with biological therapy

Aim. To evaluate skeletal muscle mass, muscle strength and physical performance in rheumatoid arthritis (RA) women with biological therapy.

Materials and methods. The study included 63 women (average age 60.3 ± 8.9 years) with confirmed RA treated with biological therapy and 117 age-matched RA patients who had never previously treated with biological therapy. Clinical and laboratory examination, evaluation of body composition using dual-energy X-ray densitometry and tests to assess muscle strength and physical performance were carried out.

Results. The frequency of sarcopenic phenotype among RA patients was 23.3 %: in those who received biological medication – 27.0 %, in the control – 21.4 % (p > 0.05). There were no differences between the groups based on the results of muscle strength assessment tests, however, patients on biological therapy performed significantly better the short physical performance battery (SPPB) and had a higher walking speed (p = 0.016 and p = 0.002, respectively). Univariate linear regression analysis confirmed the relationship of the presence of biological therapy with the functional status of the muscles according to the results of SPPB (b* = 0.24; p = 0.018) and walking speed (b* = 0.28; p = 0.006).

Conclusion. The frequency of sarcopenic phenotype among patients with RA was 23.3 % and was comparable in those who received biological therapy and without it. There were no differences in muscle strength depending on the presence of biological therapy, but the functional status of skeletal muscles was significantly better in women who received such treatment.